The present disclosure relates generally to bearing assemblies, and more particularly, to positional determination of a drive shaft in an active magnetic bearing assembly.
Generally, a bearing assembly may be used to facilitate rotational motion of a drive shaft running through the bearing assembly, for example, by constraining motion of the shaft to a desired path and/or reducing friction between the drive shaft and other components. Accordingly, bearing assemblies may be utilized in rotary machine systems such as turbo compressor systems, gas turbine systems, vacuum pump systems, and the like. In some such systems, a bearing assembly may be utilized on a drive shaft that rotates approximately 10,000-100,000 rotations per minute (RPM). Due to the high rotation speeds and high reliability requirements, a magnetic bearing assembly may be utilized.
In some embodiments, a magnetic bearing assembly may support the shaft using magnetic levitation. For example, an active magnetic bearing assembly may include multiple electromagnets, which each generates one or more magnetic fields that exert an attractive force on the drive shaft. For example, an active magnetic bearing assembly may include four electromagnets positioned 90 degrees from one another. In this manner, the force exerted by each electromagnet may be controlled to maintain the drive shaft in a desired (e.g., centered) position. In other words, the operation of the electromagnets may be controlled based at least in part on a determined position of the drive shaft within the magnetic bearing assembly.